Automatic check for hydraulic cylinders.



No. 635,848. Patented Oct. 3|, 1899.

C. N. BUTTON.

AUTOMATIC CHECK FOB HYDRAULIC CYLINDERS.

(Application filed Oct. 7, 1897.) (No Model.) 3 Sheet s8hoet I,

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No. 635,848. Patented Oct. 3|, I899. C. N. DUTTON.

AUTOMATIC CHECK FOB HYDRAULIC CYLINDERS.

(Application filed Oct. 7, 1897.)

(No Model.) 3 Sheets-Sheet 2.

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c. u. BUTTON. AUTOMATIC CHECK FUR HYDRAULIC CYLINDERS.

(Application filed Oct. 7. 1897.)

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'CHAUNOEY DUTTON, OF NEW YORK, N. .Y.

SPECIFICATION forming part of Letters Patent No. 635,848, dated October 31, 1899.

I Application filed October 7, 1897. Serial No. 654,342. (No model.)

To all whom, it may concern:

Be it known that I, OH AUNCEY N. DUTTON,

I ing is a specification.

The object of my invention is to provide effective and desirable means for preventing the occurrence of shocks in a hydraulic cylinder or stop mechanism from the sudden manipulation of the valveor application of the load.

To this end my invention, generally stated, consists in the combination, with a hydraulic cylinder and a piston or ram, either of said members being movable relatively to the other, of an automatic check mechanism actuated by the moving member for graduating and checking the flow of fluid to and from the cylinder at and adjacent to the limits of the traverse of the moving member; also, in the combination, with a hydraulic "cylinder and a piston or ram, of a supply-pipe and a checkvalve which automatically opens a passage from the pressure end of the cylinder to the supply-pipe when the movable member is at the outer limit of its stroke, in the event of the load being suddenly applied, so as to prevent shock and undue back pressure induced by sudden application of the load; also, in the combination, with a hydraulic cylinder and a piston or ram, of means for adjusting and retaining the cylinder and ramin proper oper- -ative relation.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings, Figures 1 and 2 are longitudinal central sections through a hydraulic apparatus having a fixed cylinder and a movable ram, illustrating the relation of the delivery-passage and reducers of my invention at the inner and outer extremities, respectively, of the traverse of the ram; Fig. 3, a similar section through an apparatus having afixed ram and movable cylinder, the cylinder being shown at the outer extremity of its traverse; Figs. 4 to 7, inclusive, illustrate, on a larger scale and in fuller detail, the embodiment of my invention'in a hydraulic apparatus of the'type generally indicated in- Figs. 1 and 2. Fig. 4 is a longitudinal central section through the cylinder, ram, and supply-pipe; Figs. 5, 6, and 7, transverse sections on the lines o o, w w, and 00 50, respectively, of Fig. 4. Figs. 8 to 11, inclusive, illustrate, on a larger scale and in fuller detail, the embodiment of my invention in a hydraulic apparatus of thetype generally indicated in Fig. 3. Fig. 8 is a longitudinal central section through the cylinder and ram; Fig. 9, a partial section, taken at right angles to Fig. 8, showing the manner of supporting the ram and admitting the operating fluid thereto; Fig. 10, a bottom view with the frame in section on the line y y of Fig. 9, and Fig. 11 a transverse section on the line/oz of Fig. 8.

In the drawings the invention is shown in a form suitable for use as a hydraulic buffer, stop, or controlling device adapted to limit or control the movements of a nearly-balanced memberfor example, a counterweight. When the movable member ascends, it will lift the hydraulic ram,.provided the fluid in the cylinder be allowed to waste. If the valve controlling the hydraulicsupplypipe be closed,'the movement will be arrested, while if fluid under sufficient pressure be supplied to the cylinder the hydraulic member will force down the movable member. The invention, however, is not limited to such particular use, but is of general application and may be usefully employed to gradually arrest the movements of any hydraulic apparatusof such general construction which might be liable to injury in case the moving hydraulic member moved at maximum speed until it reached a limit of its stroke and had its mo- I tion then suddenly checked.

ets 2 and as provided with aproperly-packed movable piston or ram 3, having a central bore 4, which is reduced in diameter near 1ts ends, so as to providedelivery-passages 5. A

under pressure, as an accumulator or pump, is connected to the pressure end of the cylinder 1, said supply-pipe communicating with a passage 7, extending to a hollow or tubular stem or bar 8, secured centrally in the cylin der 1. The stem 8 entersthe bore 4 of the piston .or ram 3, and its bore terminates by supply-pipe 6, leading from a source of fluid IOO an open delivery end therein, the length of the stem being such that the delivery end of its bore will be below the lower delivery-passage 5 when the ram is at the inner extremity of its traverse. The tubular stem 8 is externally fluted or ribbed, as shown clearly in the transverse sections, the spaces between the flutes or ribs forming channels or passages the aggregate transverse area of which is as great as is necessary to afford the maximum flow of fluid required through the deliverypassages 5 and the diameter over the flutes being slightly less than that of said passages. Reducer-s 9 are formed upon the stem 8, said reducers being provided for and serving the function of checking or reducing the flow of fluid through the delivery-passages 5 by making the operative outer diameter of said tube such that it will nearly fill or fit said delivery-passages. In the instance illustrated the reducers 9, which constitute, practically, enlargements of the stem or bar 8, are formed by closing up the spaces between the flutes or ribs, so as to present a continuous cylindrical instead of a fluted surface, the continuous contour being of a diameter as above specified. The reducers are located on the stem 8 in such positions that one of them will stand within one of the delivery-passages 5 of the ram when the latter is at either the inner or the outer extremity of its traverse, and the operative enlargement of diameter of the stem is preferably made a gradual one-'as, for example, by carrying out the sides of the flutes or ribs on curved or inclined lines to the continuous contour, as seen in Fig. 4. It will be obvious that the same function could be equivalently performed by the employment of a cylindrical stem increased in diameter to form reducers, the larger and smaller cylindrical portions of the stem being connected by tapering or conical portions.

Under the above construction fluid passes freely into or out of the pressure end of the cylinder from or to the supply-pipe through the spaces between the flutes of the stem 8 and one of the delivery-passages when the ram is at and adjacent to the middle portion of its traverse; but when it approaches either limit of its traverse the reducer 9 adjacent thereto enters the corresponding deliverypassage and by reducing the sectional area for the passage of fluid through the same automatically graduates and checks the flow of fluid, thereby effectually preventing shock and resultant injury to the apparatus or to its load or resistance.

The outer head 8 of the ram abuts against a beam or bumper 20 on the member 2l,which carries or constitutes the resistance or load, and in order that the apparatus may be' free from stiffness and undue back pressure in the event of the resistance or load being suddenly applied when the ram is at the outer limit of its traverse, as shown in Fig. 2, in which case the ram is to be forced back into the cylinder by the load, I provide an automatic check-valve 10, which permits the exhaust of fluid from the pressure end of the cylinder 1 into the bore 4: of the ram and thence through the pipe 8 out of the apparatus. The check-valve 10 is preferably, as shown, an annular piston-valve surrounding the stem 8 and having a lower head or ring fitting in a bushing 12 fixed in the inner head of the ram. Circumferential ports 13 in the bushing 12 communicate with passages 14, leading to the bore of the ram, and the checkvalve is normally held seated or in position to cut off communication between the ports 13 and the pressure end of the cylinder by a spring 11. Upon the exertion of unduly sudden or great pressure upon the ram by the load the check-valve is forced downwardly by the pressure in the cylinder, opening the ports 13 and exhausting fluid through said ports, the passages ll, the bore of the ram, and the tubular stem 8 to the pipe 6 and through said pipe out of the apparatus.

Figs. 3 and 8 to 11, inclusive, illustrate an application of my invention in a hydraulic apparatus having a fixed ram and a moving cylinder. In this case the pressure fluid passes through the supply-pipe 6 and passages 7 into the bore 4 of the ram 3 and thence through the delivery-passage5 in the head of the ram into the pressure end of the cylinder 1. A stem or bar 8 which in this case is solid and is externally ribbed or fluted and provided with reducers 9 near its ends similarly to the stem 8 in the construction first described, is secured centrally in the outer head of the cylinder and projects into the bore of the ram. As in the former instance, the reducers 9 nearly fill or fit the deliverypassage 5, and the spaces between the flutes or ribs afiord sufficient transverse area for the maximum flow of fluid through said passage. When the cylinder is at and adjacent to the middle portion of its traverse, fluid passes freely into or out of its pressure end through the spaces between the flutes of the stem 8 and the delivery-passage 5, and when the cylinder approaches the inner limit of its traverse the reducer 9, adjacent to the point of attachmentof the rod to the cylinder, enters the delivery-passage 5 and graduates and checks the flow of fluid. When the cylinder approaches the outer limit of its traverse, the reducer 9 on the opposite or free end of the stem enters the delivery-passage and performs the same function. I

The forms of apparatus shown are designed to be suspended, and were no provision made to adjust and retain the cylinder and ram in proper relation the moving member would slip off ofor out from the fixed member when the resistance was withdrawn or retreated. In order to retain the movable member in operative connection with the fixed member when extraneous support is withdrawn, an annular recess 15 is formed in the cylinder near one of its ends, and the outer lip of said recess is cut out sectionally, so as to provide openings 15 and constitute the female member of a bayonet-joint, the male member of which is a split ring 16, having projections 16 adapted to enter the openings 15. After the ram is entered into the cylinder the split ring 16 is put around the body of the ram, entered into the groove 15 through the openings 15, and given a partial turn, so as to be supported by the portions of the outer lip intermediate between the openings. A looking-blook 17 is then inserted into one of the openings and held into position by a setscrew or other suitable clamp 18.

I claim as myinvention and desire to secure by Letters Patent- 1. The combination of ahydraulic cylinder, a hollow or tubular ram fitting therein, and having delivery-passages of smaller diameter than its bore adjacent to its ends, apipe supplying fluid under pressure to the cylinder, and a tubular stem communicating with the supply-pipe and extending into the bore of the ram, said stem being of a diameter slightly less than the delivery-passages of the ram, adjacent toits ends, and being intermediately reduced in transverse area.

2. The combination of a hydraulic cylinder, a hollow or tubular ram fitting therein, a sup= ply-pipe leading into the bore of the ram, and

a check-valve controlling a port for the exhaust of fluid from the cylinder upon the eX- ertion of undue pressure upon the ram by the load.

3. The combination of a hydraulic cylinder, a hollow or tubular ram fitting therein, a supply-pipe leading into the pressure end of the cylinder, a tubular stem communicating with the supply-pipe and extending into the bore of the ram, through a delivery-passage of larger diameter therein, and a check-valve surrounding said stem and controlling aport between the pressure end of the cylinder and the bore of the ram.

4. The combination of ahydraulic cylinder, a hollow or-tubular ram fitting therein and havinga collar or reduction of bore adjacent to each of its ends, a tubular stem leading into the bore of the ram, and anenlargement on said tubular stem adjacent to its end which projects into the ram, said enlargement fitting each of the collars of the ram and serving to graduate and check the motion of the ram at or near each of the limits of its trav erse.

OHAUNCEY N. DUTTON. Witnesses:

PAUL SEMoT, F. N. GLEASON. 

